/*
 * Copyright (2023) The Delta Lake Project Authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package io.delta.kernel.internal.lang;

import java.util.Optional;
import java.util.function.Supplier;

public class Lazy<T> {
    private final Supplier<T> supplier;
    private Optional<T> instance = Optional.empty();

    public Lazy(Supplier<T> supplier) {
        this.supplier = supplier;
    }

    public T get() {
        if (!instance.isPresent()) {
            instance = Optional.of(supplier.get());
        }

        return instance.get();
    }
}
